For years, school officials have used detention, remedial classes, summer school and suspensions to turn around poorly behaved, underachieving middle school students, with little results. Now they are introducing a program that will pay students up to $100 per month for displaying good behavior.

Beginning in October, 3,000 students at 14 middle schools will be eligible to earn up to 50 points per month and be paid $2 per point for attending class regularly and on time, turning in homework, displaying manners and earning high marks. A maximum of $2.7 million has been set aside for the program, and the money students earn will be deposited every two weeks into bank accounts the system plans to open for them.

The system has 28 middle-grade schools. Rhee will select the schools to participate in the pilot program.

"We believe this is the time for radical intervention," Rhee said at a news conference outside Hardy Middle School in Northwest Washington. "We're very excited about this particular program."

Costs of the incentive will be split almost equally between the school system and Harvard's American Inequity Lab, which studies poverty and race issues. The program, Capital Gains, will be run by Roland G. Fryer Jr., an economics professor with the lab. Fryer also operates a pilot program in New York City public schools.

In justifying the program, Mayor Adrian M. Fenty (D) said the city has spent an inordinate amount on a school bureaucracy over the years that has failed students. Instead, he said, why not direct some of the cash to the students.

"If it seems outside of the box, it is," Fenty said.

A cash-incentive program that pays high school students as much as $500 for earning a 3 or more on an Advanced Placement test has been launched in Alabama, Arkansas, Connecticut, Kentucky and Virginia.

A study of the program released yesterday by a Cornell University economist said the incentive resulted in higher scores and an increase in the number of students attending college.

Alfie Kohn, an independent researcher whose book, "Punished by Rewards," details the downside of such programs, said incentives "undermine the very thing you're trying to promote by getting them hooked on the rewards."

Rhee said she is targeting sixth- through eighth-graders because some students in the group typically have had intractable behavior and academic problems. She said middle school is a pivotal time because many students are setting the patterns to become high school scholars or dropouts.

District middle-schoolers, often trapped in violent and academically weak campuses, typically flee the system in higher proportions than other groups, school officials said. Thirty-six percent of the city's middle-grade students are proficient in reading, and 33 percent are proficient in math, Rhee said.

The schools need to focus on "how we can ensure that students are engaged, that they are invested in their education," Rhee said. "I think it's incredibly important to make sure students take ownership of their learning."

Parents had mixed reactions to the program. Some said it was an understandable solution to an intractable problem. Others said students should not receive money to go to class. "I just totally disagree with this," said Dionne Davis, whose daughter attends seventh grade at Hardy Middle School. "I think the incentive should come from within, just to want to do well, rather than doing it for a dollar." Her daughter was not so sure.

"I think it's a good idea," said Samantha, 11. "I think middle schoolers should have rewards for getting good grades and stuff on their tests. . . . I would save it for college and maybe give some to charity."

Some school activists expressed shock and anger at the incentive.

"That's pretty pitiful," said Mary Levy, director of the Public Education Reform Project for the Washington Lawyers' Committee for Civil Rights and Urban Affairs. "It makes me sad to see we've sunk so low that we have to pay kids to show up."

Rhee said that if the incentive program is successful she could expand it to 14 other middle schools and possibly high schools. Parents can choose not to allow children to participate in the program.

Fryer said D.C. school officials will establish criteria for the program and he will track the progress. "The key is innovation, not just sitting around watching the test scores dwindle," he said.

Fryer is working with 62 schools in New York, which provides as much as $500 for fourth- and seventh-graders who perform well on a standardized test.

He said his staff is collecting data to gauge progress. Surveys of students and parents show support for the concept, he said. Results showed that 96 percent of the schools participating in the program reported that they were excited about the money; 91 percent reported an increased focus on exams; and 59 percent reported better classroom performance.

"The kids unquestionably love it. Whether that is translating into higher performance, I can't tell you for a fact" until a report is released in October, said David Cantor, spokesman for the New York Department of Education. The program, funded by private donations, cost $400,000 last year.

A program in Virginia is paying students for passing AP scores at 14 high schools in rural and high-poverty areas across the state.

Students who receive grades of 3 or more receive $100 per test, said Paul Nichols, president of Virginia Advanced Study Strategies. The program also trains AP teachers, subsidizes test costs and provides extra materials to AP classes. It began in spring, but has had an immediate effect on enrollment.

"The numbers of students in these schools that have signed up to take AP classes has more than doubled," Nichols said. "In the small rural schools, it has tripled."

The District's incentive program is in line with Rhee's efforts to break new ground with her approach to urban school reform. She garnered national attention with her contract proposal that offers teachers salaries well above $100,000 in exchange for relinquishing tenure and seniority rights. She is scheduled to speak on an education panel at the Democratic National Convention in Denver next week.